I really like the Magnolia Bakery cookbook (there are sequels, as well, but I don't own those). It's a smallish collection of cookies, cakes, cupcakes, pies, and I've made probably 7 or 8 recipes and everything has turned out PERFECTLY. Especially the orange & white chocolate chip cookies, my favorites!

For preserves, I highly, highly recommend Preservation Kitchen by Paul Virant.

I have tried several recipes from that book, and all of them are amazing. The brandied cherries are to DIE for (as in, the last time I opened a jar to garnish drinks at a party, they disappeared without making it to the drinks. They're amazing). The pickled beets are sweet and flavorful and taste like sweet beets and rosemary (and not like vinegar, which is my issue with most pickled beets) and are wonderful with sweet potatoes and goat cheese and black pepper for cocktail parties. The pickled leeks gave the most amazing boost to my last recipe of stuffing.

Seriously. I hesitated over the price, but I could hug this book. Everything tastes so good, and it's stuff that actually gets eaten by people who usually wouldn't touch a chutney.

Mark Bittman how to cook everything vegetarian (and how to cook everything has lots of vegetarian friendly things too!)

Nourishing Traditions by Sally Fallon

"Food in Jars" by Marisa McClellan is my favorite cookbook for all things canning. It has fantastic pictures and the recipes are clear and well written.

I have a lot of baking cookbooks and I think the perfect one to start a collection is Baking: From My Home to Yours, by Dorie Greenspan. It has a lot of great classic recipes and they are beautifully explained.

I second Preservation Kitchen. It's wonderful.

The America's Test Kitchen Baking Book is amazing. It has pretty much every baking recipe you would ever need, and they are all thoroughly and precisely tested.

I second Food in Jars, especially if you're interested in small-batch preserving (which is what she focuses on). For baking, I tend to reach for my favorite everyday cookbooks and turn towards the baking sections. In particular, I'm thinking of the Complete Tassajara Cookbook, Super Natural Every Day, and The New Basics.

1) Deborah Madison's Vegetarian Cooking for Everyone!
2) Determine your favorite ethnic foods, and then buy the most comprehensive books on them (warning this can be addictive)
3) For baking, check out Alice Medrich and David Leibovitz.
4) For canning, in this order: Linda Ziedrich's books, Canning for New Generation, and Tart & Sweet

I would recommend Put 'em Up! by Sherri Brooks Vinton. It's on my wish list right now and from glancing through the amazon listing, it's comprehensive (pickling, canning, freezing, etc). It's endorsed by one of my fave (vegetarian/vegan) food bloggers at neverhomemaker.com.

Baking Illustrated

My favorite baking cookbook is probably Sur La Table's "The Art and Soul of Baking"

As a vegetarian, my current obsession is "Plenty" by Ottolenghi. The recipes are delicious, and the photographs are gorgeous.

Oooh yes I love to bake and preserve my cookbooks!

Preserving cookbook: Preserving by Oded Schwartz and Small Batch Preserving by Topp and Howard. Food in Jars and Wild Fermentation: The Flavor, Nutrition, and Craft of Live-Culture Foods are on my wish list.

baking/cooking: I like Mollie Katzen's cookbooks for veggie cooking: Moosewood cookbook, Enchanted Broccoli Forest - etc. Marcella Hazan, Essentials of Classic Italian Cooking.

Baking -- love the Dorie Greenspan book, but often get annoyed because she doesn't use weights, and a few of her recipes have needed modifications as a result. Still, it is an excellent book.

Also love Nigella's How to Be a Domestic Goddess. It may sound flippant, but is actually very, very good. And if you get a British, as opposed to American, edition, you will get weights.

Bread Alone is still one of the best bread books, ever, and Baking with Julia is fun.

I love Nick Mangione for baking too -- his cookie book is my go-to cookie reference, and I have quite a few cookie books. Although again, I wish he provided weighted measures alongside the cups; recipes are more reliable that way.

I use David Leibovitz recipes a fair bit, so should look into his cookbooks too.

Darn, Rosaak beat me to it too.

Oh! Don't know how I could have left her off, because ultimately, I do make a lot of Martha Recipes -- but Martha Stewart books, of course! She has a Baking Handbook, as well as a pie book, both of which are great.

Nick is better for cookies I find, but I do make a lot of his cakes too, from his cake book.

This one is good too, for more typical American fare:

http://www.amazon.com/Vintage-Cakes-Timeless-Recipes-Cupcakes/dp/1607741024/ref=sr_1_1?s=books&ie=UTF8&qid=1350055131&sr=1-1&keywords=old+fashioned+cakes

And then there is the excellent King Arthur's Baking Companion!

oops! Sorry Nick! It's Malgeiri!! (not Mongione!)